NIST scientists use electron beam to unravel the secrets of an 'atomic switch'
New findings improve construction tools and knowhow for nanoscale devices
Scientists at the Commerce Department's National Institute of Standards and Technology (NIST) have used a beam of electrons to move a single atom in a small molecule back and forth between two positions on a crystal surface, a significant step toward learning how to build an "atomic switch" that turns electrical signals on and off in nanoscale devices.
The results, described in the Aug. 18, 2006, issue of Science,* are the first to be published about work at NIST's new Center for Nanoscale Science and Technology (www.nist.gov/public_affairs/releases/cnst.htm).
"It's still futuristic to talk about a real atomic switch but we're getting closer," says physicist Joseph Stroscio, lead author of the paper. In addition, by applying the findings to nanoscale fabrication on semiconductors and insulating thin films, it may be possible to develop new classes of electronic and magnetic devices constructed atom by atom.
In the work described in Science, NIST physicists used a custom-built, cryogenic scanning tunneling microscope (STM)--which provides a voltage and beam of electrons at its needle-like tip--to perform several different types of atomic scale measurements and manipulations. NIST theorists performed calculations of the atoms' electronic structure, which confirmed the experimental results.
A molecular chain of one cobalt atom and several copper atoms set upon a surface of copper atoms was constructed atom by atom using the STM in an atom manipulation mode. Then the STM was used to shoot electrons at the molecular chain and its effect on the switching motion of the cobalt atom was measured.
Last reviewed: By John M. Grohol, Psy.D. on 30 Apr 2016